Use of Ultrasound for the Assessment of Fluid Responsiveness in Critically Ill Patients

The concept of fluid responsiveness (FR) is used clinically to indicate a significant increase in cardiac output (CO, or cardiac index) in response to an intravascular volume expansion or other maneuvers that increase preload [1]. Therefore, assessment of FR is of paramount importance in the daily practice of intensive care unit (ICU) physicians dealing with critically ill patients. However, performing a proper assessment of FR is a challenging aspect in the management of ICU patients [2]. Importantly, both hypo- and hypervolemia are associated with poorer outcomes in the critically ill patients [3]. Moreover, the concept of fluid tolerance and of aggressive fluid removal are gaining large attention in the recent literature, and new studies are ongoing to investigate the importance of such aspects [4–6].